Erythema Nodosum

General Information
Erythema Nodosum is an inflammatory reaction deep in the skin. The reaction consists of tender red lumps or nodules that may range from 1 – 5 centimeters. Erythema nodosum commonly occurs over the shins, and may occasionally arise on the arms or other areas. Conditions that are associated with erythema nodosum include medications (sulfa-related drugs, birth control pills, estrogens), strep throat, Cat scratch disease, fungal diseases, infectious mononucleosis, sarcoidosis, Behcet’s disease, inflammatory bowel diseases (Crohn’s disease and ulcerative colitis), and normal pregnancy. Treatments for the condition include anti-inflammatory drugs and cortisone by mouth or injection. To reduce inflammation a healthcare provider may prescribe Colchicine. Erythema nodosum does not threaten internal organs and the long-term outlook is generally very good.

Epidemiology
Peak incidence occurs between 20-30 years of age. Women are 3-6 times more commonly affected than men are

Etiology
Medications (sulfa-related drugs, birth control pills, estrogens), strep throat, cat scratch disease, fungal diseases, infectious mononucleosis, sarcoidosis, Behcet’s disease, inflammatory bowel diseases (Crohn’s disease and ulcerative colitis), and normal pregnancy.

Pathogenesis
Inflammatory reaction deep in the skin

Clinical
Tender red lumps or nodules ranging in size from 1 to 5 centimeters

Histology
Panniculitis with acute and chronic inflammation in the fat and around blood vessels

Bibliography
1. “Erythema Nodosum” (Online) 2003. http://www.medicinenet.com/erythema_nodosum/article.htm (visited: March 17, 2008) 2. “Erythema Nodosum” (Online). http://www.medterms.com/script/main/art.asp?articlekey=17662 (visited: March 17, 2008)

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 Erythema Nodosum